A windmill is a machine that converts the energy of wind into rotational energy by

means of vanes called sails. Originally, windmills were developed for milling grain for

food production. In the course of history, the windmill machinery was adapted to

many other industrial uses. An important non-milling use is to pump water, either for

land drainage or to extract groundwater.

Windmills in antiquity

Heron's wind-powered organ

The windwheel of the Greek engineer Heron of Alexandria in the first century AD is

the earliest known instance of using a wind-driven wheel to power a machine. [4]

[5] Another early example of a wind-driven wheel was the prayer wheel, which was

used in ancient Tibet and Chinasince the fourth century.[6] It has been claimed that

the Babylonian emperor Hammurabi planned to use wind power for his ambitious

irrigation project in the 17th century BC.

Horizontal windmills

The Persian horizontal windmill

Hooper's Mill, Margate, Kent, an 18th-century European horizontal windmill

The first practical windmills had sails that rotated in a horizontal plane, around a

vertical axis.[8] According to Ahmad Y. al-Hassan, these anemone were invented in

eastern Persia as recorded by the Persian geographer Estakhri in the 9th century.[9]

[10] The authenticity of an earlier anecdote of a windmill involving the

second caliph Umar (AD 634–644) is questioned on the grounds that it appears in a

10th-century document.[11] Made of six to 12 sails covered in reed matting or cloth

material, these windmills were used to grind grain or draw up water, and were quite

different from the later European vertical windmills. Windmills were in widespread

use across the Middle Eastand Central Asia, and later spread to China

and India from there.

A similar type of horizontal windmill with rectangular blades, used for irrigation, can

also be found in 13th-century China (during the Jurchen Jin Dynasty in the north),

introduced by the travels of Yelü Chucai to Turkestan in 1219.[13]

Horizontal windmills were built, in small numbers, in Europe during the 18th and 19th

centuries,[8] for example Fowler's Mill at Battersea in London, and Hooper's Mill

at Margate in Kent. These early modern examples seem not to have been directly

influenced by the horizontal windmills of the Middle and Far East, but to have been

independent inventions by engineers influenced by the Industrial Revolution.

Vertical windmills

Due to a lack of evidence, debate occurs among historians as to whether or not

Middle Eastern horizontal windmills triggered the original development of European

windmills.  In northwestern Europe, the horizontal-axis or vertical windmill (so called

due to the plane of the movement of its sails) is believed to date from the last quarter

of the 12th century in the triangle of northern France, eastern England and Flanders.

The earliest certain reference to a windmill in Europe (assumed to have been of the

vertical type) dates from 1185, in the former village of Weedley in Yorkshire which

was located at the southern tip of the Wold overlooking the Humber estuary. [19] A

number of earlier, but less certainly dated, 12th-century European sources referring

to windmills have also been found. These earliest mills were used to grind cereals .

Post mill

A windmill on the background of the 1792 Battle of Valmy, France

Main article: Post mill

The evidence at present is that the earliest type of European windmill was the post

mill, so named because of the large upright post on which the mill's main structure

(the "body" or "buck") is balanced. By mounting the body this way, the mill is able to

rotate to face the wind direction; an essential requirement for windmills to operate

economically in north-western Europe, where wind directions are variable. The body

contains all the milling machinery. The first post mills were of the sunken type, where

the post was buried in an earth mound to support it. Later, a wooden support was

developed called the trestle. This was often covered over or surrounded by a

roundhouse to protect the trestle from the weather and to provide storage space.

This type of windmill was the most common in Europe until the 19th century, when

more powerful tower and smock mills replaced them.

Hollow-post millIn a hollow-post mill, the post on which the body is mounted is hollowed out, to

accommodate the drive shaft.[21] This makes it possible to drive machinery below or

outside the body while still being able to rotate the body into the wind. Hollow-post

mills driving scoop wheels were used in the Netherlands to drain wetlands from the

14th century onwards.

Tower millMain article: Tower mill

By the end of the 13th century, the masonry tower mill, on which only the cap is

rotated rather than the whole body of the mill, had been introduced. The spread of

tower mills came with a growing economy that called for larger and more stable

sources of power, though they were more expensive to build. In contrast to the post

mill, only the cap of the tower mill needs to be turned into the wind, so the main

structure can be made much taller, allowing the sails to be made longer, which

enables them to provide useful work even in low winds. The cap can be turned into

the wind either by winches or gearing inside the cap or from a winch on the tail pole

outside the mill. A method of keeping the cap and sails into the wind automatically is

by using a fantail, a small windmill mounted at right angles to the sails, at the rear of

the windmill. These are also fitted to tail poles of post mills and are common in Great

Britain and English-speaking countries of the former British Empire, Denmark, and

Germany, but rare in other places. Tower mills with fixed caps are found around the

Mediterranean Sea. They are built with the sails facing the prevailing wind direction.

Smock millMain article: Smock mill

The smock mill is a later development of the tower mill, where the tower is replaced

by a wooden framework, called the "smock." The smock is commonly of octagonal

plan, though examples with more, or fewer, sides exist. The smock is thatched,

boarded or covered by other materials, such as slate, sheet metal, or tar paper. The

lighter construction in comparison to tower mills make smock mills practical as

drainage mills as these often had to be built in areas with unstable subsoil. Having

originated as a drainage mill, smock mills are also used for a variety of purposes.

When used in a built-up area it is often placed on a masonry base to raise it above

the surrounding buildings.

SailsMain article: Windmill sail

Common sails consist of a lattice framework on which a sailcloth is spread. The

miller can adjust the amount of cloth spread according to the amount of wind

available and power needed. In medieval mills, the sailcloth was wound in and out of

a ladder type arrangement of sails. Postmedieval mill sails had a lattice framework

over which the sailcloth was spread, while in colder climates, the cloth was replaced

by wooden slats, which were easier to handle in freezing conditions. [22] The jib sail is

commonly found in Mediterranean countries, and consists of a simple triangle of

cloth wound round a spar.

In all cases, the mill needs to be stopped to adjust the sails. Inventions in Great

Britain in the late 18th and 19th centuries led to sails that automatically adjust to the

wind speed without the need for the miller to intervene, culminating in patent sails

invented by William Cubitt in 1813. In these sails, the cloth is replaced by a

mechanism of connected shutters.

In France, Berton invented a system consisting of longitudinal wooden slats

connected by a mechanism that lets the miller open them while the mill is turning. In

the 20th century, increased knowledge of aerodynamics from the development of the

airplane led to further improvements in efficiency by German engineer Bilau and

several Dutch millwrights.

The majority of windmills have four sails. Multiple-sailed mills, with five, six or eight

sails, were built in Great Britain (especially in and around the counties

of Lincolnshire andYorkshire), Germany, and less commonly elsewhere. Earlier

multiple-sailed mills are found in Spain, Portugal, Greece, parts of Romania,

Bulgaria, and Russia [23] A mill with an even number of sails has the advantage of

being able to run with a damaged sail and the one opposite removed without

resulting in an unbalanced mill.

MachineryMain article: Mill machinery

Gears inside a windmill convey power from the rotary motion of the sails to a

mechanical device. The sails are carried on the horizontal windshaft. Windshafts can

be wholly made of wood, or wood with a cast iron poll end (where the sails are

mounted) or entirely of cast iron. The brake wheel is fitted onto the windshaft

between the front and rear bearing. It has the brake around the outside of the rim

and teeth in the side of the rim which drive the horizontal gearwheel called wallower

on the top end of the vertical upright shaft. In grist mills, the great spur wheel, lower

down the upright shaft, drives one or more stone nuts on the shafts driving each

millstone. Post mills sometimes have a head and/or tail wheel driving the stone nuts

directly, instead of the spur gear arrangement. Additional gear wheels drive a sack

hoist or other machinery. The machinery differs if the windmill is used for other

applications than milling grain. A drainage mill uses another set of gear wheels on

the bottom end of the upright shaft to drive a scoop wheel or Archimedes'

screw. Sawmillsuse a crankshaft to provide a reciprocating motion to the saws.

Windmills have been used to power many other industrial processes,

including papermills, threshing mills, and to process oil seeds, wool, paints and stone

products.

Spread and decline

The total number of wind-powered mills in Europe is estimated to have been around

200,000 at its peak, compared to some

500,000 waterwheels.[22] With the

coming of the industrial revolution, the

importance of wind and water as

primary industrial energy sources

declined and were eventually replaced

by steam (in steam mills) and internal

combustion engines, although

windmills continued to be built in large

numbers until late in the 19th century.

More recently, windmills have been

preserved for their historic value, in

some cases as static exhibits when the

antique machinery is too fragile to put

in motion, and in other cases as fully

working mills. Around 50 working mills

are in operation in Britain as of 2009.[24]

Of the 10,000 windmills in use in the Netherlands around 1850, [25] about 1000 are still

standing. Most of these are being run by volunteers, though some grist mills are still

operating commercially. Many of the drainage mills have been appointed as backup

to the modern pumping stations. The Zaan district has been said to have been the

first industrialized region of the world with around 600 operating wind-

powered industries by the end of the 18th century.[25] Economic fluctuations and the

industrial revolution had a much greater impact on these industries than on grain and

drainage mills so only very few are left.

Construction of mills spread to the Cape Colony in the 17th century. The early tower

mills did not survive the gales of the Cape Peninsula, so in 1717, the Heeren

XVII sent carpenters, masons, and materials to construct a durable mill. The mill,

completed in 1718, became known as the Oude Molen and was located between

Pinelands Station and the Black River. Long since demolished, its name lives on as

that of a Technical school in Pinelands. By 1863, Cape Town could boast 11 mills

stretching from Paarden Eiland.

Windpumps

Windpump in South Dakota, USA

Main article: Windpump

Windpumps are used extensively on farms and ranches in the central plains and

southwestern United States and in Southern Africa andAustralia. These mills feature

a large number of blades, so they turn slowly with considerable torque in low winds

and are self-regulating in high winds. A tower-top gearbox and crankshaft convert

the rotary motion into reciprocating strokes carried downward through a rod to the

pump cylinder below. The farm windpump was invented by Daniel Halladay in 1854.[27][28] In early California and some other states, the windmill was part of a self-

contained domestic water system including a hand-dug well and a redwood water

tower supporting a redwood tank and enclosed by redwood siding (tankhouse).

Eventually, steel blades and steel towers replaced wooden construction, and at their

peak in 1930, an estimated 600,000 units were in use. [29] The multiple-bladed

wind turbine atop a lattice tower made of wood or steel hence became, for many

years, a fixture of the landscape throughout rural America. Firms such as

Star, Eclipse, Fairbanks-Morse and Aermotorbecame famed suppliers in North and

South America.

Wind turbine

Main article: Wind power

A wind turbine is a windmill-like structure specifically developed to generate

electricity. They can be seen as the next step in the developments of the windmill.

The first wind turbines were built by the end of the 19th century by Prof James

Blyth in Scotland (1887),[30][31] Charles F. Brush in Cleveland, Ohio (1887–1888)[32][33]

[34] and Poul la Cour in Denmark (1890s). La Cour's mill from 1896 later became the

local powerplant of the village Askov. By 1908, 72 wind-driven electric generators

were in Denmark, ranging from 5 to 25 kW. By the 1930s, windmills were widely

used to generate electricity on farms in the United States where distribution systems

had not yet been installed, built by companies such as Jacobs Wind, Wincharger,

Miller Airlite, Universal Aeroelectric, Paris-Dunn, Airline, and Winpower, and by the

Dunlite Corporation for similar locations in Australia.

Rønland Windpark in Denmark

Forerunners of modern horizontal-axis utility-scale wind generators were the WIME-3D in service

in Balaklava USSR from 1931 until 1942, a 100-kW generator on a 30-m (100-ft)

tower,[35] the Smith-Putnam wind turbine built in 1941 on the mountain known as

Grandpa's Knob in Castleton, Vermont, USA of 1.25 MW[36] and the NASA wind

turbines developed from 1974 through the mid-1980s. The development of these 13

experimental wind turbines pioneered many of the wind turbine design technologies

in use today, including: steel tube towers, variable-speed generators, composite

blade materials, and partial-span pitch control, as well as aerodynamic, structural,

and acoustic engineering design capabilities. The modern wind power

industry began in 1979 with the serial production of wind turbines by Danish

manufacturers Kuriant, Vestas, Nordtank, and Bonus. These early turbines were

small by today's standards, with capacities of 20–30 kW each. Since then, they have

increased greatly in size, with the Enercon E-126 capable of delivering up to 7 MW,

while wind turbine production has expanded to many countries.

As the 21st century began, rising concerns over energy security, global warming,

and eventual fossil fuel depletion led to an expansion of interest in all available forms

of renewable energy. Worldwide, many thousands of wind turbines are now

operating, with a total nameplate capacity of 194,400 MW.[37]Europe accounted for

48% of the total in 2009.

List of windmills

Israel

LocationName of mill

and coordinatesType Built Notes Photograph

JerusalemMontefiore MillJaffa Gate Mill

Tower

1857

[edit]Japan

LocationName of mill

and coordinates

Type Built Notes Photograph

Gunma Prefecture

Smock

Kamiyūbetsu Smock

Kita Smock

Sakura De Liefde Tower 1994

Shodoshima TowerThe windmill is presented to

Shōdo Island from Milos, Greece.

[edit]Syria

Location

Name of milland

coordinatesType Built Notes Photograph

HomsKrak des

ChevaliersTower

One of the towers had a windmill (far right in picture).[1]

Quneitra Trestle Pumping mill (Photo)

Tartus Smock Photo dated 2007

[edit]Taiwan

LocationName of mill

and coordinatesType Built Notes Photograph

Dongshih Tower

[edit]Thailand

LocationName of mill

and coordinatesType Built Notes Photograph

ChiangmaiHollow

post

[edit]Australia

[edit]AustraliaSee List of windmills in Australia

[edit]New Zealand

Location

Name of milland coordinates

Type Built Notes Photograph

Foxton De Molen Smock 2003 De Molen

[edit]Europe

[edit]Austria

LocationName of mill

and coordinatesType Built Notes Photograph

Podersdorf am See Tower

Retz Tower

Retz (second mill) Tower

[edit]Belarus

LocationName of mill

and coordinatesType Built Notes Photograph

MinskState Museum of Folk Architecture and Life

PostMoved

from Damatkanavichy

MinskState Museum of Folk Architecture and Life

PostMoved

from Yanushowka

Minsk Smock

Stroczycy Post

[edit]Belgium

See List of windmills in Belgium[edit]Bulgaria

Location

Name of milland coordinates

Type Built Notes Photograph

Nesebar Post

Nesebar Tower

Nesebar Tower

Pravda Post

Sozopol Post

[edit]Czech Republic

Windmill Ruprechtov , Brno

See List of windmills in the Czech Republic

[edit]Denmark

See List of windmills in Denmark[edit]Estonia

See List of windmills in Estonia

[edit]Finland

LocationName of mill

and coordinatesType Built Notes Photograph

Åland Islands Post

Åland Islands Post

Järvenpää Post

Konnevesi Konnevesi Museum Post

Korpoström, Korpo Hembygdsmuseum Post

Loviisa Smock

Pudasjärvi Post

Samppalinna, Turku Tower 1860

Seurasaari Seurasaari Open Air Museum Post

Sideby Post

Vaala Post

Östra Simskäla, Vårdö

Post

Vuonna Smock

[edit]France

See List of windmills in France[edit]Germany

See List of windmills in Germany[edit]Greece

See List of windmills in Greece

[edit]Hungary

LocationName of mill

and coordinatesType Built

Notes

Photograph

KengyelTowe

r

SzegvárTowe

r

SzentendreTowe

r

Szentes Dónát

Tower

Late C19th

TésTowe

r

[edit]Ireland

See List of windmills in Ireland[edit]Italy

LocationName of mill

and coordinates

Type Built Notes Photograph

Margherita di Savoia

Titt wind engine

Marsala (two mills) TowerPumping mills for

salt works

Mozia TowerPumping mill for salt

works

Orbetello Tower

[edit]Latvia

Location

Name of milland coordinates

Type Built Notes Photograph

Cēsis Tower

[edit]Lithuania

LocationName of mill

and coordinatesType Built Notes Photograph

Baltoji Tower

Darbėnai Smock

Obeliai Tower

Šeduva Velnio malūnas Tower

Šiauliai Žaliūkių malūnas Smock 1875-1880

Stačiūnai Smock

Stultiškiai

Smock

Telšiai Smock

MachineryMain article: Mill machinery

Gears inside a windmill convey power from the rotary motion of the sails to a

mechanical device. The sails are carried on the horizontal windshaft. Windshafts can

be wholly made of wood, or wood with a cast iron poll end (where the sails are

mounted) or entirely of cast iron. The brake wheel is fitted onto the windshaft

between the front and rear bearing. It has the brake around the outside of the rim

and teeth in the side of the rim which drive the horizontal gearwheel called wallower

on the top end of the vertical upright shaft. In grist mills, the great spur wheel, lower

down the upright shaft, drives one or more stone nuts on the shafts driving each

millstone. Post mills sometimes have a head and/or tail wheel driving the stone nuts

directly, instead of the spur gear arrangement. Additional gear wheels drive a sack

hoist or other machinery. The machinery differs if the windmill is used for other

applications than milling grain. A drainage mill uses another set of gear wheels on

the bottom end of the upright shaft to drive a scoop wheel or Archimedes'

screw. Sawmills use a crankshaft to provide a reciprocating motion to the saws.

Windmills have been used to power many other industrial processes,

including papermills, threshing mills, and to process oil seeds, wool, paints and stone

products.

An isometric drawing of the machinery of theBeebe Windmill

 

Diagram of the smock millat Meopham, Kent

 

Cross section of a post mill

 

Windshaft, brake wheel, and brake blocks in smock mill d'Admiraal inAmsterdam

 

Interior view, Pantigo windmill, East Hampton, New York Historic American Buildings Survey

 

Technical drawing of a 1793 Dutch tower mill for land drainage

Spread and decline

Oilmill De Zoeker, paintmill De Kat and paltrok sawmill De Gekroonde Poelenburg at the Zaanse Schans

The total number of wind-powered mills in Europe is estimated to have been around

200,000 at its peak, compared to some 500,000 waterwheels. [22] With the coming of

the industrial revolution, the importance of wind and water as primary industrial

energy sources declined and were eventually replaced by steam (in steam mills)

and internal combustion engines, although windmills continued to be built in large

numbers until late in the 19th century. More recently, windmills have been preserved

for their historic value, in some cases as static exhibits when the antique machinery

is too fragile to put in motion, and in other cases as fully working mills. Around 50

working mills are in operation in Britain as of 2009.

Of the 10,000 windmills in use in the Netherlands around 1850, [25] about 1000 are still

standing. Most of these are being run by volunteers, though some grist mills are still

operating commercially. Many of the drainage mills have been appointed as backup

to the modern pumping stations. The Zaan district has been said to have been the

first industrialized region of the world with around 600 operating wind-powered

industries by the end of the 18th century. Economic fluctuations and the industrial

revolution had a much greater impact on these industries than on grain and drainage

mills so only very few are left.

Construction of mills spread to the Cape Colony in the 17th century. The early tower

mills did not survive the gales of the Cape Peninsula, so in 1717, theHeeren

XVII sent carpenters, masons, and materials to construct a durable mill. The mill,

completed in 1718, became known as the Oude Molen and was located between

Pinelands Station and the Black River. Long since demolished, its name lives on as

that of a Technical school in Pinelands. By 1863, Cape Town could boast 11 mills

stretching from Paarden Eiland to Mowbray.

Windpumps

Windpump in South Dakota, USA

Main article: Windpump

Windpumps are used extensively on farms and ranches in the central plains and

southwestern United States and in Southern Africa and Australia. These mills feature

a large number of blades, so they turn slowly with considerable torque in low winds

and are self-regulating in high winds. A tower-top gearboxand crankshaft convert the

rotary motion into reciprocating strokes carried downward through a rod to the pump

cylinder below. The farm windpump was invented by Daniel Halladay in 1854.[27][28] In

early California and some other states, the windmill was part of a self-contained

domestic water system including a hand-dug well and a redwood water tower

supporting a redwood tank and enclosed by redwood siding (tankhouse). Eventually,

steel blades and steel towers replaced wooden construction, and at their peak in

1930, an estimated 600,000 units were in use. [29] The multiple-bladed

wind turbine atop a lattice tower made of wood or steel hence became, for many

years, a fixture of the landscape throughout rural America. Firms such as

Star, Eclipse,Fairbanks-Morse and Aermotor became famed suppliers in North and

South America.

Wind turbine

Main article: Wind power

A wind turbine is a windmill-like structure specifically developed to generate

electricity. They can be seen as the next step in the developments of the windmill.

The first wind turbines were built by the end of the 19th century by Prof James

Blyth in Scotland (1887), Charles F. Brush in Cleveland, Ohio (1887–1888)[32][33]

[34] and Poul la Cour in Denmark (1890s). La Cour's mill from 1896 later became the

local powerplant of the village Askov. By 1908, 72 wind-driven electric generators

were in Denmark, ranging from 5 to 25 kW. By the 1930s, windmills were widely

used to generate electricity on farms in the United States where distribution systems

had not yet been installed, built by companies such as Jacobs Wind, Wincharger,

Miller Airlite, Universal Aeroelectric, Paris-Dunn, Airline, and Winpower, and by the

Dunlite Corporation for similar locations in Australia.

Rønland Windpark in Denmark

Forerunners of modern horizontal-axis utility-scale wind generators were the WIME-

3D in service in Balaklava USSR from 1931 until 1942, a 100-kW generator on a 30-

m (100-ft) tower,[35] the Smith-Putnam wind turbine built in 1941 on the mountain

known as Grandpa's Knob in Castleton, Vermont, USA of 1.25 MW[36] and the NASA

wind turbines developed from 1974 through the mid-1980s. The development of

these 13 experimental wind turbines pioneered many of the wind turbine

design technologies in use today, including: steel tube towers, variable-speed

generators, composite blade materials, and partial-span pitch control, as well as

aerodynamic, structural, and acoustic engineering design capabilities. The

modern wind power industry began in 1979 with the serial production of wind

turbines by Danish manufacturers Kuriant, Vestas, Nordtank, and Bonus. These

early turbines were small by today's standards, with capacities of 20–30 kW each.

Since then, they have increased greatly in size, with the Enercon E-126 capable of

delivering up to 7 MW, while wind turbine production has expanded to many

countries.

As the 21st century began, rising concerns over energy security, global warming,

and eventual fossil fuel depletion led to an expansion of interest in all available forms

of renewable energy. Worldwide, many thousands of wind turbines are now

operating, with a total nameplate capacity of 194,400 MW. Europe accounted for

48% of the total in 2009.